family and food

I have been visiting my family for the past couple of days. I love it. I love being with my sisters and mom and driving around and not feeling lost (like I do in Seattle), but it's like when an alcoholic goes to his favorite bar and all his drinking buddies are there and he tries to abstain from having a drink himself. It is so hard. I mean, I revert back to old habits and behavior that I know is not healthy, nor is it conducive to my goals for a better me. I'm like a junkie, and all self-control and will power are thrown out the window as I embrace the gooey cheese filled burrito, or the mammoth size slice of pizza. What happens to me? Why can't I overcome these gorge fests? It's depressing, because I already know that the past two weeks of my "good" behavior will be thwarted when I get on the scale on Tuesday.
But it brings me to my topic. For me, when I am with family I engage in unhealthy eating habits. I know that others out there have similar situations when it comes to family. Maybe it is not food like me, but somehow we always fall in to the "role" we've been assigned in the family, and then we react to it. For me, its eating. Not that I eat because I am emotionally filling a void that has been left open from traumatic experiences, but more so, because everything my family does together centers around food. So, I eat a lot when i am with them.
So, I am kinda feeling a bit frustrated and disappointed in myself, because I know that I am not acting like a person who wants to lose weight, but more of someone who is a food junkie. How do I stop all this insanity. How do I change behaviour that has been instilled for a lifetime? I can't give up my family, nor do I want too... but what do I do? I obviously don't have the`right knowledge or strategies to get me through this time, and it's not even a holiday. If anyone has any answers i would love to hear them... (just a small plea for help)